If you're renting a car, I'd say DAL. I hate the car rental shuttle experience at DFW. But if you're getting picked up & dropped off (by friend, or rideshare) then DFW is better; more curb space means less congestion, and the airport layout and plethora of checkpoints means you can get from curb to gate in just a few minutes if you have pre-check or even priority/elite access.

If you have time to kill and no lounge access, DAL is probably a nicer overall terminal; DFW is dependent on which terminal you end up at.